1. Field of the Invention
The present invention relates to an ink, an ink-jet ink, an ink tank, an ink supply device, and a method for introducing ink to the ink tank, as well as an image recording device.
2. Related Background Art
The serial scan system has been used for an ink jet recording device, which comprises a carriage that moves in a primary scanning direction, a recording head as a recording means and a changeable ink tank as an ink container both mounted on the carriage. With this recording system, an image is recorded on a recording medium by repeating scanning of the carriage in the first scanning direction and the movement of the recording medium in a second scanning direction.
When a subminiature printer suitable for a PDA, a camera, etc. is realized by using such a serial scanning recording system, the size of the carriage must be small, so that the capacity of the ink tank to be mounted on the carriage must be extremely small.
Thus, when the capacity of the ink tank on the carriage is very small, frequent exchange of the ink tank will be necessary, or it may happen even a case where the ink tank must be changed in the middle of the recording operation.
Thus, to solve the above problem, an ink supply system called a pit-in ink supply method has been proposed. According to this method, ink is supplied from the separate main tank to the sub tank on the carriage with a proper timing whenever the carriage comes to a predetermined waiting position.
More specifically, whenever one sheet of the recording medium is printed, for instance, the carriage is positioned at a predetermined position and the main and the sub tank on the carriage are connected with a proper timing, and ink is supplied from the main tank to the sub tank. Thus, the problem relating to the ink capacity of the sub tank on the carries is solved.
In the above pit-in ink supply method, the sub tank contains an ink-absorbing member such as sponge inside, and ink is introduced into the sub tank from the main ink tank through an ink inlet due to the negative pressure in the sub tank. The negative pressure in the sub tank is achieved by sucking from an air outlet of the sub tank.
The present applicant has already filed a patent application for an invention concerning the above pit-in ink supply method, where a film or membrane called a gas-liquid separation film (membrane) that passes gas but not liquid is provided at the air outlet also called an atmosphere communication opening.